Water contamination and esophageal cancer at Gassim Region, Saudi Arabia

Between January 1980 and December 1982, 183 patients with histologically confirmed carcinoma of the esophagus who were referred to a tertiary referral hospital were studied. Thirty-two (17%) patients were referred from Gassim Region at the north central part of Saudi Arabia. In contrast, only 5% of total cancer patient referrals were from this area. A case-control study showed a significant regional difference within Saudi Arabia and the most referrals from Gassim area. A prospective case-control study showed persistently high numbers of referrals from that region during 1983-1987. When patients from Gassim Region were compared with those referred from other locations, no statistical differences were noted between the two groups except for the source of drinking water. Water analysis from Gassim area showed a high solid content with elevated levels of calcium, magnesium, and to a lesser extent, chromium iron, cadmium, and cobalt. Traces of petroleum oil were found in five of six water samples from Gassim during 1983, compared with 3 of 49 samples from other areas. Mutagenicity tests on water specimens form Gassim Region indicated the presence of possible carcinogens. It is being suggested that the high prevalence of esophageal cancer in this region may be related to contamination of water by impurities such as petroleum oils. Malnutrition, particularly vitamin A deficiency, as well as other factors may have promoted such malignancies.